Suggested Bolt Action Cartridge Conversions With A New Barrel

Any .270 or .30-06 (left) rifle is an excellent choice for rebarreling to .280 Ackley or .35 Whelen (right) if you want to see a nice improvement in field performance. The .280 AI is a 7mm Mag ballistically, the .35 Whelen approaches a .338. They also burn less powder than their belted twins, work well with 22" - 24" barrels and hold one more in the magazine. Feeding issues are nonexistent as they use the same .30-06 based cartridge cases and are good for non-handloaders as outstanding factory loads are available.

By rebarreling your rifle with a premium barrel rather than simply buying a new rifle with a standard factory barrel you are right to expect a significantly better result in not only enhanced ballistic performance, but also a big improvement in accuracy, appearance and pride of ownership. On top of it all, you'll enjoy this level of performance tailor-made to your specific requirements, are able to convert an old hunting rifle to a more modern tactical or target rifle, a heavy rifle to a featherweight sporter, etc..

Because of this we are getting several questions daily about possible cartridge options when rebarreling so I've prepared some guidelines below. The reasons for doing this are numerous, but as a serial barrel-switcher I've learned from my own mistakes that some conversions are far easier to pull off than others.

Here are a few options for improving your rifle's accuracy and ballistic performance:

The (l-r) .222, .223, .204 Ruger, 6mm-204 and 6.5 Grendel were all designed to work well in the same receivers and magazines. The 6mm-204 will get about all there is out of a case this size - 2800 fps with a Sierra 85 gr. Gameking bullet. The 6.5 Grendel will require a new bolt face on your bolt action or MSR because the case is of larger diameter, but it takes your rifle solidly into the 200 lb. game class and significantly improves down-range performance with its streamlined 123 grain bullet (A-Max or SST) @ 2580 fps..

Short Sction - Small
".17 Rem, .204 Ruger, .222 Rem, .223 Rem, .223 Ackley Imp, 222 Rem Mag Ackley Imp, .223 Wylde, 5.56 NATO, 6mm-.204 Ruger, 6x45, 6x47, .300 Whisper"

Short Action - Standard
".224 WBY, .22 BR, .22-250 Ackley, .220 Swift, 6mm BR, .243 Win, 6mm Rem, .250 Savage, .257 Ackley Imp, .260 Rem, 6.5-08, 6.5 Creedmoor, 7mm-08 Rem, .284 Win, .308 Win, .338 Federal"

Short Action - Magnum
".223 WSSM, .243 WSSM, 6mm WSM, .257 WSM, 6.5 WSM, 6.5 Rem Mag, .270 WSM, 7mm SAUM, 7mm WSM, .300 SAUM, .300 WSM, .300 RCM, .325 WSM, .350 Rem Mag"

The (l-r) popular .22-250, .243 and .308 all use the same (.473") bolt face and are excellent choices for a new barrel. The 7mm Rem SAUM and the .300 Win Short Magnum are in the (slightly larger .535") short mag family. Converting your .308 to a short mag will require some bolt-face work (or a bolt-swap) and is best accomplished with new magazine parts or a DM kit to be assured of reliable feeding.

Long Action - Standard
".240 WBY, 6mm-06, .25-06, 6.5-284 Norma, 6.5-06, 6.5x55, 6.5x57, .270 Win, .280 Ackley Imp, .30-06, .338-06, .35 Whelen, .375 Whelen"

Long Action Magnum
".257 WBY, .257 Ultra, .264 Win Mag, .26 Nosler, .270 WBY, 7mm Rem Mag, 7mm STW, 7mm RUM, .300 Win Mag, .300 WBY, .300 H&H Mag, .308 Norma, .30-338, .300 RUM, 8mm Rem Mag, .338 Win Mag, .340 WBY, .338 RUM, .375 Ruger, .375 RUM, .416 Rem Mag, .416 Ruger"

(l-r) .264 Win Mag, .300 Weatherby, 300 Rem Ultra Mag, .375 Ruger, .375 Rem Ultra Mag, .375 H&H Mag. Since they all have the same .532" - .535" rims, rebarreling is all that's usually required on a 700. The author notes from personal experience, considering the .375 (and .416) Ruger's more modern case design and shorter length, it is a better choice for converting standard belted magnum rifles (like the .264 Win, 7mm Rem and .300 Win magnums) to take serious big-and-dangerous game bullets than the H&H.

Long Action Magnum XL
".30-.378 WBY, .338 Lapua, .378 WBY, .416 Rigby, .460 WBY"

The next thing to consider (assuming your cartridge will fit into the receiver) is to keep the smoothest, most reliable possible cartridge feeding. While it's true you can easily swap bolts out to make your .30-06 into a .300 Mag, the next question you have to ask yourself is whether or not your conversion will feed well. There's an easy way to accomplish this and a hard way.

The easy way to be sure your new cartridge will feed like greased-lightning is to treat your rifle to a new detachable magazine upgrade for the appropriate round if it's available. Literally all of the DM's we carry (M4, M5 and H-S) feed the next round from the center of the magazine, eliminating the various internal mag boxes, springs and followers that came with the rifle. Additionally, by bypassing the receiver's feed rails and ramp you are assured that it will feed perfectly, especially if, for example, you are upgrading from a .30-06 to a .300 Mag (or a belted magnum to an Ultra, a .223 to a .243, etc.) by having the bolt altered or replaced.

The 6.5 Creedmoor is an excellent choice for rebarreling your .243 or .308 Win rifle.

That said, some of the easiest ways to get improved performance and keep your standard factory bottom metal is by simply having the new barrel chambered for a cartridge that's based on the same cartridge family. For example, one of the flattest-shooting, most accurate cartridges in the .243 / .308 Winchester family is the exciting new 6.5 Creedmoor. Similarly, nearly any old .25-06, .270 or .30-06 can be easily rebarreled to the long-range powerhouse .280 Rem Ackley Improved and some very fine 140 and 160 grain factory loads had for it directly from Nosler that feed perfectly in unaltered receivers.

With the ideal case shape and dimensions (.534" x 3.340") for most of today's long action rifles, the 26 Nosler is an excellent candidate for rebarreling factory belted magnum (or ultra magnum) rifles. We're hearing a lot about it since SHOT!

This of course is a partial list however I think you'll find the vast majority of factory rounds as well as wildcats well-represented - just compare the dimensions within each category to your proposed cartridge.

Any gunsmith that specializes in rebarreling will be more than happy to answer any questions you may have, as will we by phone, email or chat. Just remember, as a rule of thumb, the closer your new round is to the important dimensions of case rim diameter and cartridge overall length as the original round, the easier your conversion will be.